Catalysis of hydrocarbons by gel-type catalysts



Patented Dec. 17, 1946 CATALYSIS F HYDBOCABBONS BY GEL-TYPE CATALYSTS Robert E. Burk and Everett 0. Hughes, Cleveland Heights, Ohio, asslgnors to The Standard Oil gohliipany, Cleveland, Ohio, a corporation of No Drawing. Original application January 20.

1942, Serial No. 427,524.

Divided and this application September 11, 1942, Serial No. 457,928

8 Claims. (Cl. 196-52) Various suggestions have been made for the preparation of supported catalysts carrying oxides nd metal of the sixth periodic group, the supp rt or carrier being granules of clays, magnesium oxide or aluminum oxide. and the chromium oxide and molybdenum oxide being coated on the surface of such granules. Aluminum oxide in such conditions is largely masked from contact with raw material being catalyzed, and action which might be contributed is correspondingly lost. Moreover because of the lack of molecular intermingling, any stabilizing action the aluminum oxide might contribute is low. We have found that catalysts of superior properties may be prepared in a three-component system -in which the components are particularly intimately commingled and brought together in co-precipitation of gel type, the resultant components being oxides of aluminum, molybdenum and chromium. Aluminum is toward the basic end of the periodic system. and molybdenum and chromium are toward the acid end. Whether under the conditions of preparation we apply, a loose combination of the components may result, or a more effective contact and opportunity for action of the components is involved, is not known, At any rate however, catalysts of the present invention are capable of outstanding action, and with very little difficulty from coke production.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particuiarly pointed out in the claims, the following de-- scription setting iorth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

The most desirable manner of preparation of the present catalysts is such that gives a maximum intimacy of mixture of the three components. The aluminum oxide component should predominate, and the molybdenum oxide and chromium oxide should not exceed 30 moi per cent each and should not be less than 2 mol per cent each. the aluminum oxide making up the remainder, and the molybdenum oxide may be in greater or smaller amount than the chromium oxide. Illustrative modes of preparing the catalysts are as follows:

A solution of sodium or potassium aluminate is neutralized with an acidic solution containing chromic acetate or sulphate and ammonium paramolybdate (NH4)eM01O24.4H2O. Preferably 2 gether, in the ratio to give the desired catalyst compositions. In effect, the chromium and molybdenum are precipitants tor the aluminum, and vice versa, so that perfect homogeneity is obtained in the precipitate. The hydrogen ion concentration in the solutions is adjusted such that the final mother liquor of the precipitated catalyst is 9 to 11 pH, preferably 10. Where the high concentrations of molybdenum oxide are involved, i. e. on the order of 20 to 30 moi per cent, lower pH values than may be used, as down to 6, thereby providing substantially complete in- V corporation of the molybdenum, After precipitation the catalyst is washed, and dried. The drying is preferably carried out at around 140 F. until in a hard granular condition, then the material is ground and meshed to size, after which it is given a final drying in which the temerature is gradually. raised to that at which it is to be used, e. g. 900-1000 F. The catalyst may then be cooled and preferably be given a short wash with boiling water until molybdenum blue shows in the wash water. Such wash removes any water soluble salts that have come to the surface of the catalyst in the drying operation.

As another example: Ammonium paramoiybdate and chromium and aluminum acetates and sulphates or nitrates are mixed in a single solution having a pH below 4. Then ammonium hydroxide or other alkali hydroxide is admixed to precipitation, and the product is washed and dried. Preferably, the drying involves a firststage drying at around 140 F., grinding and sixing, and finally heating at high temperature, and final washing. as above.

As another example: Alumina and chromium salts in solution, such as the above salts, are precipitated with ammonium hydroxide or alkali hydroxide, and the slurry of the precipitate in the mother liquor or after filtration and washing is mixed with a solution of ammonium paramolybdate such that the final pH is 6 to 11. The highest pH in this range is used which will allow substantially complete incorporation of the molybdenum oxide with the other oxides. The prodnet is washed and dried, and preferably the detail of the drying first at around 140 .C., grinding and sizing, and finally drying at high temperature, then washing, may be applied.

Ammonium paramolybdate, which is preferred, as in the foregoing, may in some cases be substituted by other soluble compounds of molybdenum. including the reduced form known as molybdenum blue and even lower valence forms.

the solutions are pumped together or flowed toe fllle ly. s illustrating Proportions 0! components which may be applied, the following examples may be noted.

I. A mixture of 0.6 mol summon a, 10.6 parts by weight of (NH4)uMO70u.4Ha0, and 35 parts by weight of concentrated H2804, is diluted to form 22,000 parts of solution. Another solution is prepared by diluting to 2,000 parts of water a product of reaction of 2.4 mols of heavy aluminum hydrate and 3.0 mole of NaOH. The two solutions are brought together at a suitable rate, the pH being maintained at 9.7-9.9. The precipitate is aged for about two hours, filtered and washed with about 24,000 parts of water. and is then dried, preferably at 140 F, for about 110 hours and for 2 hours at 900 F. under line vacuum of 50-100 mm. Hg. In this catalyst the mo] ratios of components may be 70 mol per cent aluminum oxide. 2 mol per cent of molybdenum oxide, and 20 mol per cent of chromium oxide.

11. A catalyst is made up to a composition of gel-type oxides in proportions of 70 A1210 Mo: 20 Cr. oxides, by diluting a mixture of 0.6 mol Cr (Cal-1302):, 30 parts by weight of concentrated H2504 and 53 parts by weight of NH4) aMOrOuAHzO to 22,000 parts water solution, and then admixing this at a suitable rate and a solution made by reacting 2.1 mol of A1(OH)3 and 3.7 mol of NaOH to form NaAlOz and diluting to 2,000 parts. The pH of the mother liquor is 9.7-9.9. The precipitate is aged for about 18 hours, filtered and washed with about 24,000 parts of water. The catalyst is dried, e. g. at 140 F. for 60 hours and at 900 F. for 1 hour under vacuum after which it is quenched from 500 F. in boiling water. The catalyst is then preferably washed until molybdenum blue shows in the wash water, and it is therr further dried at 140 F. for about 18 hours and at 500 F ior about 2 hours under vacuum.

III. 2.84 mol of A1(NO3):.9H2O and 0.06 mol of Cr(N:)a.9H;O and 0:6 mol of (NI-I4) nMOvOnAHaO are dissolved in 20.000 parts 01' water. A solution of 490 parts by weight of concentrated NHiOH to 3,000 parts of water is mixed with the aforesaid solution, with a resutlant pH of 7.1. After aging for about two hours, the slurry is filtered and washed on the press with 20,000 parts of water. and the cake is dried for about 16 hours at about 140 F., and is sized to ten to twenty mesh, and finally heated to 900 1 under vacuum, the latter temperature being held for about an hour.

The present three-component catalysts are particularly eflective for operation on hydrocarbons, etc., in dehydrogenating and cyclicizing. Thus, hydrocarbons of at least six carbon atoms may be aromatized, and aliphatic hydrocarbons or paraflins and olefins and naphthenlc hydrocarbons or their mixtures, naphthas, distillates. and non-benzenoid hydrocarbons in general may be operated upon. Where aromatic compounds are also present in the stock, these may be preliminarily removed if desired, as for instance by solvent extraction, formation of complexes with halides, etc., but removal of aromatic compounds is not necessary. The feed rate of hydrocarbons to the catalyst may be 01-10 liquid volumes/volume catalyst/hour.

Aromatization with the present catalysts is most effectively carried out with the presence of hydrogen under pressure. Partial pressures of hydrogen up to 300 pounds per square inch may be used, preferably 50-300 pounds per square inch.

The hydrogen may be passed in with the naphtha for instance, using 0.1-10 mols of hydrogen per mol of naphtha feed. The hydrogen may be irom any convenient source. In some cases it is desirable to re-circulate a portion of the cit-gases. The gas may be added to the naphtha vapors all at once before admitting to the catalyst zone, or may be added in successive portions to successive trays for the catalyst contact. Temperatures of 850-1200 F. are applied. And at thehigher temperatures correspondingly shorter contact times may be used.

After contacting with the catalyst. aromatic and unsaturated hydrocarbons may be extracted from th product if desired, for example by sulphur dioxide or high boiling amine or hydroxide compounds or combinations of such or other solvents. and the undissolved or non-benzenoid portion may be re-contacted with the catalyst. In some cases the product as coming from the catalyst zone may be distilled and used directly for motor'fuel etc. And, in some cases a narrow cut may be used as charging stock and pure aromatics may be separated primarily by distillation.

In tests against two-component catalysts of aluminum and chromium or aluminum and molybdenum, operating on a 52.5 A. P. I. gravity Illinois naphtha of 190-408 F. boiling range, at 980 F. catalyst zone temperature. and 100 pounds per square inch pressure. with 3 mols of hydrogen to 1 mol of naphtha, and 1.3 vols. of liquid feed per volume of catalyst per hour, comparative results were as follows:

Percent aromatics and oloiins in product In another test. with catalyst composition mol per cent aluminum oxide, 10 mol per cent molybdenum oxide and 20 mol per cent chromium oxide. at l,000 Ft, 200 pounds total pressure, hydrogen to naphtha mol ratio of 3.5:1, and flow rate 1.23 v. v. h., the product showed 63 per cent of aromatics and oletlns, and 0.8 per cent of coke was deposited on the catalyst.

A particularly interesting distinction is that although chromium and molybdenum are in the same periodic group, it is found that molybdenum oxide containing catalysts have an additional function of isomerizing hydrocarbons, which action is not obtained by chromium-aluminum oxide catalysts.

This application is a division of our application Serial No. 427,524, filed January 20, 1942.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A pressure of treating hydrocarbons, which comprises subjecting a naphtha in the presence at hydrogen in partial pressure of 50-300 pounds per square inch, at a temperature of 850-1200 F., to the action of a contact mass consisting of aluminum, chromium and molybdenum gel type oxides in the particularly intimate relationship which results irom their co-precipitation from an aluminum salt and a chromium salt and a hydroxide precipitant and ammonium paramolybdate, in proportions to provide 10 mol per cent of molybdenum oxide, 20 moi per cent oi chromium oxide. and 70 moi per cent oi aluminum oxide.

2. A process of treating hydrocarbons, which comprises subjecting a hydrocarbon of at least six carbon atoms in the presence of hydrogen in partial pressure 01' 50-300 pounds per square inch, at a temperature oi 850-1200 F., to the action of a contact mass consisting 01' aluminum, chrmium and molybdenum gel type oxides in the particularly intimate relationship which results from their co-precipitation from an aluminum salt and a chromium salt and a hydroxide precipitant and ammonium paramolybdate, in proportions to provide 70 to 78 moi per cent of aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount of not less than 2 mol per cent and not more than 20 mol per cent.

3. A process or treating hydrocarbons, which comprises subjecting a naphtha to the action or elevated temperature and a contact mass consisting of aluminum, chromium and molybdenum from gel type oxides in the particularly intimate relationship which results from their co-precipltation from an alkali metal aluminate and chromium compound and ammonium paramolybdate.

4. A process 01 treating hydrocarbons, which comprises subjecting a naphtha, at elevated temperature, to the action of a contact mass consisting of a gel type oxide co-precipitated from components providing mol per cent of molybdenum oxide, 20 moi per cent oi chromium oxide, and 70 moi per cent 01 aluminum oxide.

Patent No. 2,412,600.

5. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon of at least six carbon atoms to the action of elevated temperature and a contact mass consisting of aluminum, chromium and molybdenum gel type oxides in the particularly intimate relationship which results from their co-precipitation from an alkali-metal aluminate and chromium compound and ammonium paramolybda-te.

l0 6. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon of at least six carbon atoms, at elevated temperature. to the action 01' a contact mass consisting of a gel type oxide co-precipitated from components providing 10 moi per cent of molybdenum oxide, mol per cent of chromium oxide, and 70 mol per cent of aluminum oxide.

7. A process 01' treating hydrocarbons, which comprises subjecting a naphtha, at elevated tem- 20 perature, to the action of a contact mass consisting of a gel type oxide co-precipitated irom components providing 70 to 78 mo] per cent of aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount oi as not less than 2 mol per cent and not more than 20 mol per cent.

8. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon at at least six carbon atoms, at elevated temperature, to the action of a contact mass consisting 01' a gel type oxide co-precipitated from components providing to 78 mol per cent oi aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount or not less than 2 mol per cent and not more than 20 mol per cent.

ROBERT E. BURK. EVERE'I'I C. HUGHES.

December 17 1946.

ROBERT E. BURK ET AL.

It is hereb certified that errors appear in the above numbered patent requiring correction as to lows: In the grant, line 6, and in the heading to the printed specification, line 3', title of invention, before CATALYSTS insert OiXIDE; column 5, line 28, claim 3, strike out "from before gel; and that the Silld Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 25th day of February, A. D. 1947.

LESLIE FRAZER,

First Assistant Gommissioner of Patents.

which results irom their co-precipitation from an aluminum salt and a chromium salt and a hydroxide precipitant and ammonium paramolybdate, in proportions to provide 10 mol per cent of molybdenum oxide, 20 moi per cent oi chromium oxide. and 70 moi per cent oi aluminum oxide.

2. A process of treating hydrocarbons, which comprises subjecting a hydrocarbon of at least six carbon atoms in the presence of hydrogen in partial pressure 01' 50-300 pounds per square inch, at a temperature oi 850-1200 F., to the action of a contact mass consisting 01' aluminum, chrmium and molybdenum gel type oxides in the particularly intimate relationship which results from their co-precipitation from an aluminum salt and a chromium salt and a hydroxide precipitant and ammonium paramolybdate, in proportions to provide 70 to 78 moi per cent of aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount of not less than 2 mol per cent and not more than 20 mol per cent.

3. A process or treating hydrocarbons, which comprises subjecting a naphtha to the action or elevated temperature and a contact mass consisting of aluminum, chromium and molybdenum from gel type oxides in the particularly intimate relationship which results from their co-precipltation from an alkali metal aluminate and chromium compound and ammonium paramolybdate.

4. A process 01 treating hydrocarbons, which comprises subjecting a naphtha, at elevated temperature, to the action of a contact mass consisting of a gel type oxide co-precipitated from components providing mol per cent of molybdenum oxide, 20 moi per cent oi chromium oxide, and 70 moi per cent 01 aluminum oxide.

Patent No. 2,412,600.

5. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon of at least six carbon atoms to the action of elevated temperature and a contact mass consisting of aluminum, chromium and molybdenum gel type oxides in the particularly intimate relationship which results from their co-precipitation from an alkali-metal aluminate and chromium compound and ammonium paramolybda-te.

l0 6. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon of at least six carbon atoms, at elevated temperature. to the action 01' a contact mass consisting of a gel type oxide co-precipitated from components providing 10 moi per cent of molybdenum oxide, mol per cent of chromium oxide, and 70 mol per cent of aluminum oxide.

7. A process 01' treating hydrocarbons, which comprises subjecting a naphtha, at elevated tem- 20 perature, to the action of a contact mass consisting of a gel type oxide co-precipitated irom components providing 70 to 78 mo] per cent of aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount oi as not less than 2 mol per cent and not more than 20 mol per cent.

8. A process of treating hydrocarbons, which comprises subjecting a non-benzenoid hydrocarbon at at least six carbon atoms, at elevated temperature, to the action of a contact mass consisting 01' a gel type oxide co-precipitated from components providing to 78 mol per cent oi aluminum oxide and the remainder molybdenum oxide and chromium oxide each in an amount or not less than 2 mol per cent and not more than 20 mol per cent.

ROBERT E. BURK. EVERE'I'I C. HUGHES.

December 17 1946.

ROBERT E. BURK ET AL.

It is hereb certified that errors appear in the above numbered patent requiring correction as to lows: In the grant, line 6, and in the heading to the printed specification, line 3', title of invention, before CATALYSTS insert OiXIDE; column 5, line 28, claim 3, strike out "from before gel; and that the Silld Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 25th day of February, A. D. 1947.

LESLIE FRAZER,

First Assistant Gommissioner of Patents. 

